With thoroughly optimized plotting engine Thunderplot is able to visualize datasets with millions of rows in real time.
Thunderplot extracts numeric data from every field of dataset ignoring extra characters.
In addition to csv/tsv parser Thunderplot has «just extract all numbers» mode in which you can visualize any unprepared data, like debug logs or command line utilities output.
Thunderplot is an UI-based interactive application. There's no need to learn yet another programming language for making plots.
Thunderplot is completely offline. It does not send data to anywhere and does not perform any processing outside of the application.
Thunderplot is a native OS X application and it doesn't require X11 or hidden browsers to run.
The size of Thunderplot is just ~4 Mb. Its memory footprint is ~20-25 Mb (without your data loaded).